The Worthington advance. [volume] (Worthington, Minn.) 1874-1908, 1887-03-24
HOW TO MAKE GLASS.

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Philadelphia Press:
c. Hanford Henderson, professor Of
chemistry aud physics in the Indus;
trial Training School, lectured at
Franklin institute recently on 'Glass
Making" After briefly retailing the
history Of the art ofmaking glass, and
what glass was, Mr.: Henderson said:
'The operation Of glass-makins re:
quires both skill and patience; nicely
in the mixture of the materials and
aelicacy and dexter,ty in the manu-
tacture of the finished product. There
is no industry so benefited by tho
discovery Unnatural gas as this. Euro.
pean manufacturers havelong used ar
tificial gas, it having been found that
smoke and sulphurous fumes from the
coal affected the clearness of the pro-
duct. Where. in this country, nat
ural gas is not obtainedable. man.
ufactured gas is taking the place OF
Goa! in the principal furnaces. In the
furnaces huge pots Of fire-clay, with q
capacity of 1,4OO to 1000 pounds
of material. are filled with the
mixed substances called the batch
composed Of sand, lime and carbon
ate or sulphate of soda in varying
proportions. Into a chamber beneath
them the burninggas streams. Above
each pot is an opening into the cham
Der in which it stands, throug h which
the blowpipe is dipped into its con.
tents. The blowpipe is a heavy tube
of wrought iron, its lower end some
what flanged.
In making the window glass, the OPP
orator repeatedly dips his pipe into
the molten glass, until on it's end is q
mass of fused glass. Whirling this
rapidly and dexterously it assumes
pear-liks shape. The operator
blows into the pipe, mould
ing the huge bubble as it grows TO the
size and shape of a carboy. The blow
ing now ceases, and the operator
swings his bubble in q pit beneath his
platform, until by it's weight it length
ems into cylinder and coois to hard
ness. The top and bottom OF this
cylinder are ingeniously got rid OF,
and a cold iron is run along one side
the remaining cylinder. making a
straight crack through its entire length.
&c 1p,{1
permost, as it is heated it falls out in
to a fat plate and is ''ironed smooth"
by fiat piece of wood on the end of
a long bar. Lastly, it is put into the
annealing furnace, heated and allow
ed to cool very gradually, to tougher
the glass. 1t may then be cut up into
panes. Crown glass ia made by gath
ering the mass in the end of the pipe,
blowing small bubble and transfer
ring it to an iron bar. The opening
left by the blowpipe is gradually en-
larged as the mass is whirled until the
mass becomes circular fiat disk. It's
disadvantages are its variable thick
hess and the smallness of the panes.
Plate glass is of the same compost
ton as the former, but purer materi-
oils are used. 1t is cast on an iron or
bronze table from a huge ladle swung
from the furnace to the table. Rollers
pass over it to secure uniform thick
ness. The result is rough slab, only
translucent. 1t is made smooth with
sand and emery, and polished with
burnt sulphate of iron.
In making the batch for optical
glass lead is used instead of lime. This
branch of the art reaches its highest
perfection in America, and all the I'M
portant lenses for telescopes are made
on this side of the Atlantic. Another
fat glass is seen in the car windows,
the design being pressed into the heat
ed pane, and the marks subsequently
polished.
Mosaic glass is translucent, colored
unevenly by arsenic, tin and other
compounds, and is coming into use in
preference to stained glass, its dura-
bility and richness of shading being
superior to the latter.
1t is cast in small pieces, the opera
tor himself not knowing exactly how
the product will look, and the artist
consequently can not have his pieces
made to order A memorial window
in Milwaukee, made of this glass, the
subject being Christ Leaving the Hall
of Justice contains 200 figures.
Mr.. Yunk then made in miniature,
from glass tubes, some of the articles.
Briefly describing the process he said:
'Hollow-ware is either blown or press.
ed. The furnace used in making it Is
the Ferrari or tank furnace, the hot
air impinging on a constantly renewed
heap of material in a rever6eratory
chamber, the fused product flowing
away into tank, with openings above
it similar to those in other furnaces. By
this process work is kept up continu
ously in blast from fall to spring. The
mass on the blow pipe is put into a
mould, which closes upon it while the
operator blows into it; the necks are
finished afterwards in an oxy-hydro-
gen flame. Finer holloware is mould
ed in the air entirely, its surface being
much brighter and smoother.
Pressed glassware is made by pour
ing the motion glass into a metal
mould, and another mould fitted to
its inside surface, pressed heavily into
it. 1t is made in imitation of cut
glass, but it distinguishable from it
by the dizziness of its edges, caused by
the product shrinking as it cools. Cut
glass, however, is now made from it,
the article being pressed into shape
and the design ground clear and sharp
with fine copper wire covered with
sand"
Can't Tell the Difference,
ut is O fact" said somewhat
famous mixer of fancy drinks re.
Gently. "that there are very few good
judges of liquor. 1t is a very old
chestnut to set out whisky when
brandy is called for, and not one in